Resistance shunt adapter



Get. 31, 1939. R KAMM RESISTANCE SHUNT ADAPTER Filed March 28, 1958 JZaZerZ' a (IttornegS.

Patented Oct. 31 1939 UNITED STATES RESISTANCE SHUNT ADAPTER Robert A. Kamm, Hartford, Conn., assignor to Electra Sales Corporation, Hartford, Conn, a corporation of Connecticut Application March 28, 1938, Serial No. 198,540

4 Claims.

The present invention relates to Christmas tree lighting and other electrical circuits, and has for an object to provide an adapter embodied in the form of a resistance shunt for use at each lamp and which is so .constructed that it may be quickly and easily mounted in the lamp socket between the same and the lamp for maintaining the circuit closed when the lamp is burned out.

Another object of the invention is to provide a shunt adapter of the type using granular substances as the resistance and wherein the positioning and removal of the lamp in the adapter automatically so disturbs the vgranular substance as to reinstate the condition of resistance after the condition has been partly broken down by the shunting of the circuit therethrough.

The invention also aims to provide an adapter which when in position is seated in the lamp socket and which itself provides a socket for the base of the lamp and which provides practically a continuation or a part of the normal socket so that the conductor parts are housed within the casings or husks of the socket and the adapter so as to prevent accidental short circuiting or dangerous exposed contact surfaces to surrounding objects, such as when the lighting circuit is mounted on a Christmas tree.

Another object of the invention is to provide an adapter which may be used in an ordinary tree lighting circuit to provide a shunt resistance at each lamp, and wherein the lamp bulb when blown may be discarded andsubstituted with a new bulb without loss or destruction of the shunt resistance.

With-the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawing, wherein like symbols refer to like or corresponding parts throughout the several views.

Figure 1 is a side elevation of a resistance-shunt adapter constructed according to the present invention.

Figure 2 is a vertical central section taken through the same,

Figure 3 is a similar view but with the adapter mounted in a lamp socket.

Figure 4 is a detail perspective View of the combinedcentral contact and'agitator of the adapter, and

Figure 5 is a planview of the upper end of the central contact.

Referring now to the drawing, theadapter is provided with an upper socket portion 10 and a lower'plug' portion H'suitably connected together, the socket portion In for receiving the base of the ordinary electric bulb and the plug portion I l adapted to engage in an ordinary electric light socket, such as shown at l2 in Figure 3. The

adapter socket I0 is constructed of an internal shell which is screw-threaded for the reception of the base of the lamp. The upper end of the socket or shell I0 has an outturned flange I3 which is frictionally seated Within the Upper end of a casing or husk Id of any suitable configuration and which is of insulating material for protecting the upper end of the adapter. The lower end of the shell Ill carries an insulating disc l5 through which is ,slidably and rotatably disposed .the upper end portion of a central contact [6. The contact 16 may be of hollow rivet form, as shown particularly in Figures 4 and 5, and which is headed or flanged and which is turnedover or peened at opposite ends to provide contact heads I! at opposite ends disposed in central axial alignment with the socket I0 so that the upper head I! may be engaged by the central contact in the base of the lamp. The upperliead ll of the central contact [6 is preferably roughened as by slots [8, or the like, to provide a frictional contact surface between the upper end of the contact l6 and the lower end .of the bulb central contact. This insures that the contact it will be turned to some extent during the final turning or seating of the bulb into the adapter socket. The lower end of the socket I0 is provided with an inwardly stepped flange H! which supports the insulating disc l5 and which also provides an annular rim about which may be seated the upper end of the threaded shell of the plug I I. The upper end of the plug shell H is soldered asat 2 0 to the lower end of the socket shell in so as to hold the two shells together as a unit when they are assembled as shown in Figures 2 and 3. Of course it is possible to manufacture the shells I0 and- H in one piece but it is found more expedient and practical to make them in two pieces and assemble them as shown.

The :lower end of the plug shell H is closed by an insulating disc 2i forming the bottom of the plug shell and the latter is hollow to provide a receptacleinto which is placeda granular shunt resistance material ,22, such as aluminum particles whichmay be coated with graphite, or other suitable substance. The granular body 22 is filled within the shell II to a height which provides .a body sufficient to maintain .a bridging between the central contact l6 and the side wall of :the shell II so that whether the adapter is used in upright position, as shown in thedrawing, or invertedposition, or is disposed in any-angular position of use, there will always be maintained a sufficient quantity of the granular substance 22 between the central contact and the shell to provide the required shunt resistance should the lamp burn out. The central contact [6 passes downwardly through the insulating bottom 2| of the plug H and the lower head ll of the contact is adapted to engage, as shown in Figure 3,

the central contact 23 of the lamp socket I2. The contact I6 is of slightly greater length than the distance between the upper and lower faces of the insulating discs I5 and 2| so that as a central contact I6 is engaged by the base of the lamp bulb the contact I6 may be not only turned to fications may be made in the details of construcdisturb the granular body 22 within the plug but also given a slight axial movement. The granular particles 22 are relatively small so that a very slight movement on the part of the central contact I6 is sufiicient to disturb the positions of the granular particles and consequently reestablish the desired resistance through the body.

The lower end of the hub or casing I4, indicated at 24, is made yieldable, either by an inherentsoftness or elasticity of the material or in any other suitable manner so that when the adapter is used in different types of sockets the plug portion II may be turned down to its full extent in the ordinary lamp socket I2. In the present instance the outer casing 25 of the lamp socket is shown with a relatively large flare or bell-shaped upper end so that the lower end of the adapter shell I4 may freely enter the upper end of the socket shell 25 and thus the plug II of the adapter may be readily and fully seated within the lamp socket. However, there are many Varieties of lamp socket shells 25 and in a great many of these shells the upper ends are not flared but are considerably reduced so that the lower end 26 of the adapter casing would abut the lamp socket casing and prevent the full seating of the plug H in the socket. To take care of this condition, the lower end of the casing I4 is yieldable so that it may be compressed during the final turning of the plug II into the socket to insure the full seating of the plug therein.

It will be apparent that the adapter may be screwed into the lamp socket I2 so that the upper socket-portion Ill of the adapter rises from the lamp socket and the lamp bulb may be screwed in the ordinary manner in the adapter socket IE]. As the base of the lamp bulb is given the final twist or turn in the socket ID, the central contact of the lamp bulb frictionally engages the upper head ll of the adapter central contact I6, wisting and longitudinally moving the contact I6 sufiiciently to disturb the body of particles contained in the plug shell II about the central electrode I6.

' rent passing through the lamp socket I2 passes to the shell plug ll through the granular body 22 and to the central contact I6 back to the circuit. The result is that the resistance set up by the granular particles 22 is overcome to such an extent as to maintain the circuit closed and with the desired resistance, equal substantially to that of the burned out bulb.

To replace the lamp in the circuit, it is preferable to unscrew the adapter from the socket I2 and to then remove the adapter from the bulb.

The advantage of this is that the rotatable and slidable contact I6 of the adapter is given greater freedom of motion, and the granular body 22 is disturbed by the removal of the adapter from the lamp socket and the handling of the adapter in removing it from the base of the lamp bulb.

This is not necessary however as the central contact I6 is under all conditions given sufiicient turning movement as the old bulb is removed from the adapter socket I0 and the new bulb is screwed into the same.

It is obvious that various changes and modition and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims:

What is claimedis:

1. In a resistance shunt, a socket for the base of a lamp, a hollowed chambered portion connected to the bottom of the socket, a granular resistance body disposed in the chamber, and a central electrode movably mounted through the bottom of the socket and through the chamber in contact with the granular body, said central contact adapted for movement by the base of the lamp bulb when moved in the socket to disturb the relative positions of the particles of the granular substance to reestablish a resistance subsequent to passage of a current therethrough.

2. A resistance shunt comprising a lamp socket having a hollowed chamber at its lower end, a central electrode rotatably and slidably mounted through the bottom of the socket and through said chamber and a body of granular particles enclosed in said chamber about said central electrode, the movement of the base of a lamp in said socket into and out of engagement with said central electrode adapted to move the latter for disturbing the positions of the granular particles in the chamber.

3. A resistance shunt adapter comprising a socket shell, a plug shell connected to the socket shell and providing a chamber beneath the socket shell, insulating elements disposed at the 0pposite ends of the plug shell, a body of granular particles disposed in the plug shell, and a central electrode longitudinally slidable and rotatably mounted in the insulating elements at opposite ends of the shell and extending through the body of granular particles, the upper end of said central contact adapted for engagement with the base of a lamp bulb when placed in the socket and adapted to be disturbed thereby to change the positions of the granular particles about the central electrode. and thus increase the electrical resistance through the body of granular particles.

4. A resistance shunt adapter comprising a socket shell adapted to receive a lamp base therein, a plug shell extending from the lower end of the socket shell and providing a chamber therebeneath, a central contact extending through the plug shell and the chamber therein and adapted at its upper end for engagement with the central contact of a lamp base, a body of granular resistance material disposed in the chamber within the plug shell about said contact, and a casing surrounding and enclosing the socket shell and having a lower resilient end adapted for compression within a lamp socket of the narrow upper end type to insure a full seating of the plug shell in a lamp socket and the sealing of the adapter casing against the upper end of the casing of the lamp socket.

ROBERT A. KAMZM. 

